Aside: Boundary Layer Separation

This clip explains why boundary layers separate and compares boundary layers with the Couette and Poiseuille flow studied in chapter 3. It then explains some of the consequences for flow around wings and other objects.

[@TheOnlyRaceEngineer]

Fantabulous, concise and to the point mechanics. No drama. Thank you for such a great explanation of the rudimentary concept. I especially liked it when you mentioned the Kutta condition. Thanks a million.

[@dantemakoya]

A Mechanical Engineering student from South Africa, appreciate you sir! God bless you!

[@umbertocostabitencourt3695]

That lecture was very well explained. Thanks!

[@rombajj]

Such a good explanation, thank you!

[@sushilkumarmaurya623]

Very good explanation. I appreciate your work. Got this. Thank you!

[@akinyilmaz99]

Thanks for simple explanations.

[@CoconutSundae]

Great lecture, thanks for uploading!

[@amartyathigale898]

Very well explained, kudos and thanks to you sir.

[@akm.iftekhar5859]

Many many thanks for the lecture

[@xyrildanmanuel783]

9:33 "...coated in condensed milk.... of all things" some small and quick humor right there

[@giuseppe654]

you explain things ver well. In university, there is a lot of confusion between separation and turbolence

[@sibusisosithole9778]

Best Explanation. Thank you

[@alimozaffar6884]

how a good lecture!! thanks alot

[@streens]

Brilliant. Thank you!

[@fmp1976]

What software did you use for presentation? Looks great!

[@Serenelove520]

good video, but could you explain why in the viscous example at 13:15, the right side has less pressure than the left side? Because as I understood, air turning creates pressure, and there is air being turned on the right side as well, why does it have less pressure on that end?

[@dieter2020]

Very well explained!

[@alitabarzadi3137]

Thank you.

[@Luxolus]

Very helpful, thanks!

[@Gorusuur]

Great explanation

[@alexsinek9937]

Awesome lecture!

[@chuksiwundu7299]

Beautiful lecture

[@BertBert2323]

This is really good!

[@chowonjang2220]

very helpfull for fluid . thanks !!

[@xwdoctor4420]

thank you

[@ravindergupta5457]

I didn't understand why the velocity on curved surface ( inviscid flow ) is higher at the top??? it should me minimum at the top and same on left and right side which is higher than the top. correct me of i am wrong.

[@sumeetkadam22]

Ravinder Gupta As we go from high pressure zone to low pressure zone velocity of fluid increases thats why velocity curve is broad at topmost point than start and end point.

[@goodmann4503]

@@sumeetkadam22 why the pressure at the start and at the end is higher than the pressure at the top of the curved surface?

[@navinpn410]

@@goodmann4503 flow area decreases initially and hence pressure increases reaches max value and then due to increase in flow area pressure increases. Similar to convergent divergent area.

[@XPLAlN]

The answer to this question is that when the airflow curves there must be lower pressure towards the centre of the curve. The streamline cannot curve towards the high pressure side.

[@IanSGI]

Thank you! Now I truly understand what it means when the 'telltales' on the leech of the mainsail are actually telling me. It's one thing to do know that when a telltale does 'x' then I need to do 'y', but understanding exactly what the physics helps even more. Separation for the (race) win!

[@atillaus9168]

great really

[@balaganesann5225]

Why we consider inviscid flow

[@alexsinek9937]

Usually inviscid flow is employed during boundary layer considerations, as they tend to deal with very high Reynolds numbers (sometimes with limits to infinity) and thus eliminating the need to consider viscosity during the first (theoretical) approach (they often approximate the REAL case very well).

[@shubhendu2882]

Can someone explain why the pressure at the topmost point is lower than the other points?

[@youssouflebbar7329]

The molecules have always the highest speed in the x direction when they're at the top. This is because when they reach a curved surface, they need to deviate, hence their velocities will have a component in the y direction.The way you can think about it is that for instance if you have a stagnation point let say at the left side of the cylinder, the x velocity of the fluid molecule will be null, hence the fluid molecules will kind of accumulate there as in proximity their velocity is small, more molecules imply more pressure.

[@Serenelove520]

Youssouf Lebbar could you explain why in the viscous example at 13:15, the right side has less pressure than the left side?

[@rahulj3265]

hi sir , Could you please give some reference books to follow along ..

[@aerodynamico6427]

He says corrects himself four times: at 11:58, 13:23, 13:55, and 14:12 (confused between back of the wing and tip) and says "I'm sorry" thrice after mixing up stagnation and separation. He's drunk!

[@sibusisosithole9778]

Best Explanation. Thank you